1. Field of the Invention
The present invention refers to a granulating machine having a sieve in the form of a truncated cone in which a rotor is disposed which is mounted on a shaft, the shaft rotating in at least one bearing and being coupled to a lateral driving element which is arranged under the sieve and the rotor, the machine thus being designed for in-line operation.
2. Description of the Related Art
Such a machine is known for example, from U.S. Pat. No. 5,330,113. The rotor of this machine turns on bearings which are accommodated in a protective casing of a gear transmission. The casing is arranged under the rotor, the latter being driven by a lateral driving shaft and by the bevel gears which are mounted on the rotor shaft and on the driving shaft. The axial position of the rotor on its shaft, the play between the rotor and the sieve, is adjustable by increasing or reducing the number of washers which are disposed between the upper end of the rotor shaft and the bottom of the rotor bore. It is obvious that in order to vary the axial position of the rotor, the latter must be dismounted from its shaft which, in addition, is impossible without stopping the machine.
U.S. Pat. No. 4,773,599 discloses a granulating machine having a device which allows an adjustment of the axial position of the rotor and thus of the play between the rotor and the sieve. The adjustment is effected by means of a disk which is accessible from the top side of the rotor and the sieve, an in-line operation being impossible due to the disk, the rotor axis, and the bearings of the rotor which are disposed above the rotor.
A first object of the present invention is to eliminate these drawbacks. This object is attained by a granulating machine wherein the rotor including its shaft is axially displaceable by an adjusting device acting upon the shaft of the rotor underneath the rotor and the sieve. Preferentially, the adjusting device is acting upon the bearing of the rotor, which is axially displaceable.
Another drawback of the known machine is the fact that the bevel gears which are transmitting the rotation of the driving shaft to the rotor shaft must be in an oil bath, which requires an absolute tightness of the casing in which the bevel gears and the bearings of the rotor shaft and of the driving shaft are accommodated. However, the risk of leakages cannot be totally eliminated, and it is easy to imagine the damages caused by oil leakages, particularly if the machine is used for the treatment of pharmaceutical products. Thus, another object of the present invention is to prevent these drawbacks. This object is attained by a granulating machine wherein the driving shaft of the rotor is driven by a belt.